Kamil Kulesza

On automatic secret generation and sharing for Karin-Greene-Hellman scheme

The secret considered is a binary string of fixed length. In the paper we propose a method of automatic secret generation and sharing. We show how to simultaneously generate and share random secret. Such a secret remains unknown until it is reconstructed. Next, we propose a method of automatic sharing of a known secret. In this case the Dealer does not know the secret and the secrets Owner does not know the shares. We discuss how to use extended capabilities in the proposed method.

On Mobile Agents Resistance to Traffic Analysis

This paper will concern itself with a formulation of a traffic analysis problem for mobile agents. It is an interesting theoretical problem as well as a critical feature when using agents on a massive scale in decision making systems. The decision making systems are applied to demanding and complex environments such as stock markets. The mobile agents used are natural targets for attacks because they provide information for decision making. The resulting information can have a value measured in millions of dollars and information of such a high value attracts potential attacks. An efficient way to attack the user of decision making systems is to learn her strategy and respond in kind. In this respect even passive observation of agents can provide useful data, namely what information they are gathering. A common first defense is to provide anonymity for mobile agents. However, what happens when anonymity is gone? What information then becomes available and what steps will the user take? Yet, the problem has not been previously formulated for such a framework. We formulate it in terms of various factors used for traffic analysis. These factors originate from different side channels that provide information on the operating agents. At the end we state a paradox, which links an excessive use of countermeasures against traffic analysis with weakening system security.

When perfect is not ideal, or mathematical methods for secret sharing

The paper is concerned with secret sharing schemes, a family of cryptographic protocols. First, we describe the basic schemes. Next, we present general secret sharing and the approach based on information theory. Finally, we outline extended capabilities of secret sharing schemes. An additional contribution of the paper is our effort to present unified terminology in Polish.

On a Check-Digit Method Based On Graph Coloring

We propose a check-digit scheme that makes use of graph vertex coloring. It complements known schemes, which rather make use of the graph structure. Our scheme can be used simultaneously with them to compensate for mutual weaknesses. We show that feasibility of the proposed scheme increases with the size of the number whose digits are checked, and with the overall probability of digit errors.